I recall an article from a long time ago that basically said “astronauts report” the moon smells like spent gunpowder and outer space smell like… I think it was ozone.
What they were actually reporting was the smell of the airlocks after they returned from their excursions. The moon has no atmosphere, so it has been accumulating dust from billions of years of asteroid impacts that have never come in contact with oxygen. Many of the chemicals in the dust are oxidative and so when it is exposed to air for the first time it rapidly oxidizes just like gunpowder!
And I think the outer space report was from space walks, and the explanation was that the first time the airlock itself was exposed to hard vacuum, the surfaces of the airlock would have a reaction that left a scent of ozone.
There was some concern when Apollo 11 landed that when they repressurized the LEM with moon dust samples inside it would start a fire. I think they had a small test article that they blew a small stream of oxygen over to ensure it wouldn't auto-ignite.
the detail that kills me is moon dust has never contacted oxygen in billions of years, so every time an astronaut came back inside they were essentially doing a chemistry experiment for the first time. the whole moon is just waiting to react with air
Terraforming is an exceptionally energetic endeavor. Even if you had the perfect combination of icy asteroids with just the right amount of water, nitrogen, oxigen etc. and the means to hurl them towards Mars, this kinetic event would be so energetic that it would take centuries to millennia before the surface would cool to habitable temperatures. it's not physically possible to do it ex in the span of a human lifetime.
Ar the scale terraforming entails, the crust reactions with the new atmosphere are closer to a rounding error.
It took about a billion years of photosynthesis on earth before all the ferrous iron dissolved in the oceans was oxidized and atmospheric oxygen concentration began to take off.
great questionprobably not poison it directly, but you'd lose a significant chunk to oxidation reactions before reaching any stable equilibrium. the surface is essentially a massive reactive sink. mars has a similar problem, the perchlorate in the soil would react badly with a lot of things we'd want to introduce.
the optimistic read is that oxidation reactions release energy and eventually reach stability. the pessimistic read is the timescale is geological.
Isn't Mars red due to oxygenation of the rocks? Is that ancient oxygenation or is there some quantity of oxygen in Mars atmosphere today? Does the atmospheric CO2 sometimes break down (maybe under sunlight) and release some small quantity of O2 or might there be another source? Might something underground be respirating atmospheric CO2?
At least some ISS astronauts describe smelling burnt metal after returning from EVA, if memory serves. (Others may smell ozone, I've just always remembered hearing burnt metal).
the exterior of the ISS is constantly exposed to small mounts of atomic oxygen, which is an incredibly strong oxidizer. probably in addition to ozone there is a huge variety of organic and inorganic oxides that get tracked in through the airlock.
Fun trivia (well, perhaps not fun) in the second paragraph: "the Long Duration Exposure Facility (LDEF), which was retrieved in 1990 after spending 68 months in LEO"
Long exposure, 68 months, right. But it was only supposed to be in orbit for 11! Challenger being destroyed on reentry made a mess of things.
>It was placed in low Earth orbit by Space Shuttle Challenger in April 1984. [...] At LDEF's launch, retrieval was scheduled for March 19, 1985, eleven months after deployment.[4] Schedules slipped, postponing the retrieval mission first to 1986, then indefinitely due to the Challenger disaster. After 5.7 years its orbit had decayed to about 175 nautical miles (324 km) and it was likely to burn up on reentry in a little over a month.[6][9]: 15
My UV sterilizing lights make my room smell like O3 Ozone and that smells nothing like spent gun-powder to me. The only other time I have smelled the same thing is when there has been mass lightening events in the sky. Were they talking about actual black powder or nitrocellulose? I've smelled black powder at the range when people bring out their antique rifles and that also does not smell like Ozone to me.
I also associate ozone with some electric motors, I think because they have brushes that arc during operation. Older power tools I encountered in the 1980s often did this, and you could see the blue arc if you looked into the vents at the right angle.
Brushless motors are popular now, but if you get the cheaper cordless tools they'll still have brushed motors. I have some Black & Decker 20V ones that do it. They tend to have less torque but I don't need Milwaukee or Makita tools just for diy around the house.
Photocopiers smell like ozone when they run if anyone’s forgotten the smell
Those are similar but sweeter. If I sterilize a room with UV it has a very distinct smell like nothing else aside from lightening and stun guns. I would UV the bathroom right now but then I have to vent the entire house and its 34F outside right now.
Hi, i am not who you asked, but i feel like i've done enough research and have some warnings. UV-C light itself is antimicrobial, but only for surfaces that the light touches, and in the case of cloth it needs to penetrate a bit.
There are at least two types of UV-C light bulbs, as well as literal ozone generators that use ceramic platen and a fan. The type of UV-C bulb that is most common on Amazon and Ali is ~254 nanometers, and _does not_ produce Ozone. It does leave a smell, but it's more like an oldschool hospital antiseptic smell. probably the smell of the dead germs, yay.
Now 185nm is actually the correct size to turn O2 around the bulb into O3 (and more oxygens too, i once read, i think, kinda like cracking hydrocarbons to make longer chains or something).
UV-C bulbs (not base, which is an edison base) that can sterilize a room in 5-15 minutes are about 15-20 CM tall, with four crystal tubes that are connected together standing up on the base. image here [0]
you must run a fan over them if you want your money's worth. they get hot, the bases get hot, it makes the most sense in non-carpeted rooms to aim the crystal down and the base up, so that is real rough on them. that took me 2 bulbs to figure out.
If you can find a reputable place to get the box with ceramic and a fan that lasts more than 5 minutes, let me know, because that's closer to what i want for bedrooms and stuff.
The UV-C 185nm bulbs work great to make a car stop stinking, too! completely removes cigarette smells, if the car hasn't been smoked in for a while. run the A/C full blast and run the bulb for 15 minutes, open the windows for 5 minutes, roll em, sniff. Still smell? another 10 minutes, in the back seat, full A/C blasting. vent, sniff. Faint smell? replace the cabin air filter. Charge customer(?)
and i'm going to respond to your followup question to the GP as well: Covid. Obviously. They were telling us it would live on groceries and deliveries and that, so i put all deliveries in my laundry room and dosed em with UV-C for a minute. CDC or whatever studies said that 10-60 seconds was more than enough to kill sars-ncov-2.
I only use it for freshening cars, rooms, bathrooms, etc now.
WARNING: Do not be in the room with any UV-C light for more than a few seconds. Do not look at the bulb for literally any more than necessary to ensure it is on and safe. they make safety goggles that wrap your entire eye sockets to protect from UV, too. if you get a 185nm bulb, either completely ventilate the room with fresh air, or leave it sealed for 60 minutes then open it up for a few minutes, all the ozone reacts and goes away or something.
UV-C hurts your skin, yes, but it will make your eyeballs literally itch. so don't, don't don't look at it. they are not blacklights.
i didn't touch the bottoms and the backs. like, put on socks, grasp box between socked feet, open box, remove the air bag packaging stuff, and if you want, UV it again. however, if you're using 185nm the ozone will get the "back" and inside. not the bottom, maybe, but if you're concerned, flip it over. If you're concerned, make sure you read research papers on exposure time of pathogens to UV-C and/or Ozone to population destruction. as i mentioned, the papers i read before i bought the bulbs said 10-60 seconds for covid. originally there was a recommendation for up to 3 minutes, but some research group went and tested shorter and shorter lengths of time. so you'd need to know the pathogen you're targeting and run it accordingly.
> WARNING: Do not be in the room with any UV-C light for more than a few seconds.
This advice does not necessarily apply to far UVC (200-235 nm), which appears to be much safer for human skin and corneas than UVC outside this specific band. More research is needed before calling it "safe" but far UVC is almost certainly less hazardous than the rest of the UVC band.
Pay close attention to wavelength when purchasing UVC light sources.
254 doesn't make ozone but; yes, i explained the two i have used and researched. i have not researched far-UVC. it's still germicidal, i still wouldn't want to be in the room with it. I had to check what wavelength "common" UV lasers are, and i'm guessing 261nm or so. If you aim that at your skin, it feels hot real quick. Kinda feels, to me, like my entire life i've been told that all UV is bad, but UV-A blockers are snake oil, etc.
I'll keep my eye out for more research on far-uvc and the possibility of getting a bulb to test.
oh by the way, i must have sent back 2 dozen "185nm" UVC bulbs from a dozen "manufacturers" because they didn't produce ozone, because they were fraudulent listings of 253.7nm bulbs - so this is why i was trying to steer people away from amazon and ali, as it's real easy to get the wrong type if you're looking for ozone. I've only managed to acquire 4 bulbs total in the last 5 years that produced ozone, and i burnt out two before someone said "put a fan on it, those bulbs are designed to be inside an air exchanger!"
I primarily use them in the bathroom to kill off mold and bacteria about once every 3 months. I open up the water heater closet, drawers, etc... then I fire one of them up. I've used them in other places but the more they are used the more I have to vent the house.
Has anything prompted you to do this? Have you been doing this for a long time? Have you noticed any changes (yes, I assume?!). Sorry for pelting you with questions, but this is so... interesting and I'm tempted to give it a shot.
Yes and it wasn't sarcastic, both things (what you said and what they said) are simply true. I think their point was not to be alarmist like you should stop breathing, but simply that everyone knows the one thing and most people don't know the other thing, and it gives scale or context to the "you don't want extra ozone".
Absolutely. I vent the house after running UV lamps using a 4400 CFM air mover. I leave the house and run errands. I have 3 of these [1]
They have a remote control that "arms" them and it starts beeping slow, the faster, then much faster then activates. It kills insects be destroying their lungs and entirely destroys mold, bacteria and even damages viral material. Hospitals run the same lamps in wings that they close down for sanitation. The entire area has to be 100% vented.
I worked for a germaphobe, and he put one of these ozone-injecting air purifiers in our tiny office. Every morning I would walk in and it felt like I was walking into a thunderstorm from the smell. No gunpowder, just thick ozone
The permissible exposure limit for ozone is 0.1 PPM.
The IDLH (Immediately Dangerous to Life and Health) level for ozone is five ppm.
That's half of chlorine which is 10 ppm.
Most major brand air purifiers put out a very minimal amount; the ionization is beneficial because it makes the really tiny (and thus most hazardous) particles clump and fall/stick to surfaces faster.
It's the offbrand units that generate lots of ozone to make people think they're "doing something", and commercial ozone generators for car/room deodorizing, that you have to be extremely careful with. Those need to be set up and then the room left for hours for the ozone to react with stuff, and then ventilated thoroughly.
Brushed DC motors (as in some drills, toothbrushes, etc.) emit ozone. Some light switches also create ozone-producing electrical arcing if you hold them perfectly between the on and off positions, or slowly cross the midpoint. (Less easy with the newer-style, less accessible rocker switches.)
> [...] Better hygiene meant that infants and young children had fewer opportunities to encounter and develop immunity to polio. Exposure to poliovirus was therefore delayed until late childhood or adult life, when it was more likely to take the paralytic form.[22]
That’s because the parent claim is known as the hygiene hypothesis and has been disproven by science, in common with anti vaccine claims. The immune system has not been shown to benefit from training, but has been shown to be damaged by illness.
Sorry for the tangent, but you sterilise a whole room with UV light? Is that efficient ? Do you do it after tidying / cleaning ? Is there a medical reason for the extra part? Is it just cool :-)
The house came with a bacteria that would normally be hard to get rid of. UV, bleach and peroxide took care of it. I just repeat the process to ensure there is no bacteria or mold. This seems to bother people in this thread which I find fascinating. A part of me wants to bring my black light to their dwelling.
I have mold problem in one of the bathrooms. What would be your recommendation? Seal off bathroom and run UV, then vent? Or do I need to do entire house? I can also seal off bathroom and bedroom. Thanks!
The ozone report was specifically about space walks. The gunpowder report was about moon walks.
Presumably, moonwalks would also have some ozone like the space walk did. But, maybe the burning-moon-dust gunpowder smell was a lot stronger than the vacuumed-metal/paint ozone smell.
Even in code where performance is a serious concern, you don't need to feel guilty about using a data structure that is an array of pointers to 4 kbyte chunks or a tree of such chunks. 4K is linear enough that using a completely flat array probably won't be significantly faster.
I’d bet the DS is the most advanced game console where it is still possible for a person to productively program it entirely via the bare metal memory map. As in: using an “SDK” that’s just a C header full of struct and array definitions at magic fixed addresses and no functions at all. Set values and the hardware does stuff.
The DS has you dealing with two cores you need to write a firmware for that have to communicate to do anything useful, a cartridge protocol to fetch any extra code or assets that wouldn't all fit into RAM at runtime, instruction and data caches, an MMU, ...
And that's without mentioning some of the more complex peripherals like the touch screen and wifi.
All official games used the same firmware for one of the cores, a copy of which is embedded into every single cartridge ROM. There's some homebrew firmwares included in the respective SDKs, but they aren't well documented for standalone use.
Granted, all of the above isn't completely impossible, but if you think of how much code you'd need to get a simple demo (button input, sprite moving across the screen), especially for a beginner, the DS requires a nontrivial amount of code and knowledge to get started without an SDK. Meanwhile, you can do something similar in less than 100 lines of ASM/C for GBA.
Agreed. I spent a lot of time programming the GBA in the early 2000s (back when the state of the art devkit was a flash cartridge writer with parallel cable...) and I consider it the last "grounded" console that Nintendo made, where you immediately and directly get to touch hardware right off the bat, without any gyrations. After having worked with the SNES in the 90s the GBA was a very familiar and pleasant platform to experience, in many ways similar to and built upon the SNES' foundation.
I've never coded for SNES, but the GBA having access to a mainline, modern C compiler is a massive buff. Also, emulators for it have always been available on practically any computer, console and mobile phone, and there's many so-called "emulation handhelds" that bring its (and similar) form-factor handheld devices to the market. If you really need an upgraded OG experience, many upgrade kits for the handheld exist as well.
None of this fixes the audio, but it sure gets damn close.
Just curious what you mean by "fixing the audio"? In GBA emulation or on the hardware?
I'm aware that if you need/want PCM audio, there's going to be mixing, probably with a software library, and significant CPU use for it. Is emulated GBA audio buggy?
One of my first gigs was Game Boy and Game Gear programming. I know the GBA allows DMG audio compatibility and, with all its constraints, well it sure does keep things simple. And emulation is reliable AFAIK.
I see what happened, I was replying to a different comment, that did mention the GBA audio, when I wrote that, but somehow ended up replying to this one.
The DS, more specifically the arm946e-s has an MPU, not a MMU (you're confusing it with the 3DS's Arm11). Not like it makes much of a difference anyway, you configure either once or twice then leave them be.
Honestly, I think why the GBA is more popular than the DS for that kind of thing is because it only has one screen (much less awkward to emulate), has high-quality emulators that are mostly free of bugs (mGBA most notably), and its aspect ratio is better than the DS anyway (3:2 upscales really well on 16:10 devices). That is to say, it's much easier to emulate GBA software on a phone or a Steam Deck than it is to emulate DS software.
gah, you're right, I was thinking of memory protection (as in, marking the relevant regions as read-write and read-execute) when I wrote MMU.
It's of course optional, and you can ignore it for trivial examples, but most games and SDKs will tweak it all the time when loading additional code modules from the cartridge.
It's just another way in which the DS is more complex to use properly without an SDK to do this for you - there's just more to think about. At least compared to how the GBA lacks all of this and the entire cartridge is mapped into memory at all times.
I agree, the GBA is a pleasure to work with. It's just a shame that the poor quality of the (stock) screens, low resolution, and lousy sound hardware make it feel like such a downgrade from the otherwise gnarlier and technically inferior SNES.
There's a pretty big renaissance of GBA clones out there right now that put better screens and speakers to the platform. And of course with emulators you can get all the modern hardware affordances for the platform.
The screen can be improved, but the resolution and sound system can't be.
The issue with the sound isn't just the speakers - you could always use headphones, after all. The GBA only has the original GB's primitive PSG (two square waves, a noise channel, and a short programmable 4-bit waveform) plus two 8-bit PCM channels. 8-bit PCM samples are unavoidably noisy with lots of aliasing, and all sound mixing, sequencing, envelopes, etc. for those channels needs to be done in software, which tends to introduce performance and battery life constraints on quality, channel count, effects, and sample rate.
The SNES, by comparison, uses high-quality 16-bit 32kHz samples, and all the places on the GBA where devs may have had to cut corners are done in hardware: eight separate channels, no need for software mixing, built-in envelopes and delay.
Compare the SNES FFVI soundtrack to the GBA version; the difference is dramatic. Frankly, using high quality speakers or headphones just makes the quality difference more obvious.
In addition to the screen and the sound, don't forget having just 2 face buttons after 4 buttons had become standard and almost mandatory. Many ports suffer mightily in the control department.
Probably? Everything else onward relies on libraries...
Though there were some fits and starts there. The N64 for example is, from what I've heard, heavily library dependent and absolutely brutal to program bare metal (GPU "microcode" that was almost like programmable shaders v0.1); even the GameCube is a significant improvement for that kind of thing.
Agreed. I’ve done trivial obfuscation for games. In my observation, if you make it trivial to hack your game, huge numbers will trivially hack it. If you make it even slightly non-trivial, the numbers decrease exponentially. The more you waste their time, put up hurdles, the lower the number of successful hackers goes.
The goal is not perfect security in all situations for all products. The goal is to make the effort required for your particular product excessive compared to the payoff.
Dunno if the link was changed or something but I had to go to the main page to see the list at the bottom https://ohmjs.org/. Hope that saves someone some searching!
Some ten years ago I used an earlier version of https://unity.com/how-to/analyze-memory-usage-memory-profili... to accidentally discover a memory leak that was due to some 3rd party code with a lambda that captured an ancient, archived version of Microsoft's C# vector which had a bug. There were multiple layers of impossibility of me finding that through inspection. But, with a functional tool, it was obvious.
Ten years before that I worked on a bespoke commercial game engine that had its own memory tracker. First thing we did with it was fire up a demo program, attach the memory analyzer to it, then attach a second instance of the memory analyzer to the first one and found a memory error in the memory analyzer.
Now that I'm out of gamedev, I feel like I'm working completely blind. People barely acknowledge the existence of debuggers. I don't know how y'all get anything to work.
A quick google for open-source C++ solutions turns up https://github.com/RudjiGames/MTuner which happens to have been updated today. From a game developer, of course XD
According to that chart 2021
was anomalously low and it has been linearly returning to normal for the past four years.
AFAICT, the general populace is anxious about AI. So, the news knows they can get clicks with “You are right to be afraid. AI bad.” Meanwhile, CEOs know they can get stock boosts by saying “We are so AI we don’t need expenses. Infinite ROI!”
Put together we’re getting a ton of scary reporting on what looks like a quite normal business cycle (at least as far as layoffs go). And, everyone being afraid to hire is the only thing actually making it self-fulfilling.
I wouldn’t call the massive levels of investment by both private equity and municipal/state governments “business as usual.” The sums being thrown down and/or promised are staggering. People/groups that lose are going to lose big.
If you have an HDR TV, preferably OLED, and miss the CRT look, check out the RetroTink 4K https://www.retrotink.com/
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